Alloy



, Patented Sept. 23, 1924.

UNITED STATES PATENT OFFICE.

RICHARD WALTER, F DUSSELDORF, GERMANY.

ALLOY.

No Drawing.

My invention refers to alloys adapted to" resist the corrosive action of acids and more especially to alloys containing silicon.'

As is well known to those skilledin the art, alloys containing a relatively high percentage of silicon owing to their being acidproof are widely employed for the purposes of chemical manufacture. Now an alloy of this kind in order to answer all requirements should contain a silicon content with-. in the limits of 8 and On the other hand such alloys are so hard and brittle 10 that they can be machined only with the aid of carborundum discs, and obviously the brittleness of the material renders it unfit for many cases. Many attempts have been made to avoid these drawbacks but u till 15 now they have, all of them, remaine unsuccessful.

I have now ascertained that by adding .boron to alloys containing a relatively high percentage of silicon the hardness'andbr t 8 'tleness of thealloys'is quite'materially 'di--' minished without their power ofresiSting. the action of acids being reduced thereby.

I haveascertained. that the hardness 0 an alloy containinglii' per cent silicon and 85 acid-proof alloy Application filed June 26, 1920. Serial No. 392,081.

per cent iron and which is so hard astoscratch glass, will be greatly reduced by the addition of as little as 0.01 percent boron, while if 0.03 to 0.04 per cent boron are added, the material can easily be turned on w the lathe, be bored and drilled, the structure of the alloy being much finer than before,

This is the more astonishing in viewof the Well known fact that for instance in the case of steel an addition of boron will greatly increase the hardness of the metal.

I claim: 1. As a new product of manufacture an acid-proof high-silicon alloy, containing an admixture of boron in efiective amounts. 2. As a new product of manufacture, an acid-proof high-silicon alloy, containing an admixture of boron in eflective amounts, but 7 not over 0.0 i% of the total.

3. As a new article of manufacture, an acid-proof high-silicon alloy, containing an admixture of boron within the limits of 0.01

and 0.04%.

4. As a new article of manufacture any highacid-proof iron-silicon alloy having a silicon content, containing an admixture of boron-in effective amounts.

5; As a new article of manufa ture, an

within the limits of 8 and 20%,and a boron content of eifective amount.

In testimony whereof I hire.

- RIGHARDWALTER;

having a silicon! content ifix my signa-- 

